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  <title>Document</title>
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  <script>
    // 1.var变量可以重复声明
    // var message = "Hello World"
    // var message = "你好, 世界"


    // 2.let/const不允许变量的重复声明
    // var address = ""
    let address = "广州市"
    // let address = "上海市"
    const info = {}
    // const info = {}

  </script>

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